Chicxulub impact produced 30-year impact winter with global cooling of 10-20°C

Researchers analyzed a 1.3-meter core from the Chicxulub crater and global K-Pg boundary sections using high-resolution organic geochemistry and climate modeling. They quantified wildfire-derived soot and sulfur aerosols that persisted in the stratosphere, producing a multi-decadal “impact winter” with surface temperatures dropping 10–20 °C and near-total darkness for the first 1–2 years. This rapid, sustained cooling matches the selective extinction of large-bodied, photosynthetic-dependent taxa while sparing deep-ocean and burrowing species.

The study’s 30-year duration estimate rests on 1,000-year-resolution proxy sampling and aerosol optical-depth simulations; however, it lacks direct year-scale resolution and assumes constant soot residence times. Comparable modern analogs, such as the 1815 Tambora eruption’s “year without a summer,” lasted only 1–3 years, underscoring how the asteroid’s global soot load exceeded any historical volcanic event by orders of magnitude.

Linking this abrupt climate shock to today’s anthropogenic warming highlights that both rapid cooling and rapid warming can trigger ecosystem collapse when change outpaces adaptive capacity. The same marine and terrestrial food-web sensitivities observed at the K-Pg boundary are now appearing in coral bleaching and insect-pollinator declines under current temperature trajectories.

Next steps include targeted coring of additional K-Pg sites and coupled Earth-system models that incorporate both soot and CO2 feedbacks to test whether similar aerosol-driven cooling could temporarily mask or accelerate greenhouse-gas-driven extremes.